1. Field of the Invention
This invention relates generally to tire pressure warning systems and more particularly is directed towards a new and improved system for providing warning signals to the operator in the event of either high or low air pressure in a tire. This invention also relates to a system for automatic replenishment of air lost from a tire while the vehicle is in motion as a means for minimizing the effects of a blowout.
2. Description of the Prior Art
In U.S. Pat. Nos. 3,489,998, 3,659,264 and 3,738,308 there are disclosed tire pressure alarm systems for motor vehicles wherein a serious change in air pressure is detected by the operator. This is done in the first patent by the means of a device fitted to the wheel adapted to generate a sonic signal in the event of an abnormally low pressure. A microphone is located in proximity to the wheel and, in the event of a signal from the device, the operator is alerted by an alarm on the dashboard, for example. In the second patent, both high and low pressures are detected by means of a reed that is vibrated by an excessive change in pressure. Again, the sensing device is located in proximity to the wheels and is activated by sympathetic vibration with the reed on the tire. Finally, the last patent discloses a wheel-mounted device incorporating an air-operated whistle responsive to both high and low pressure with sensors located in proximity to the wheels and with sensors operatively connected to an operator signaling system.
The present invention has for one of its objects the improvement in systems of the foregoing type.
A more specific object is to provide a tire pressure warning system that is quickly and easily installed. Another object of this invention is to provide a tire pressure warning system capable of discriminating between tires and also a system that is substantially insensitive to spurious noises. A further object of this invention is to provide a tire pressure warning system with a memory capability in the event of a substantial change of tire pressure occurring while the operator is not in the vehicle. Still another object of this invention is to provide a tire pressure warning system incorporated with an automatic pressure replenishing system functional while the vehicle is in motion, or at rest.